1. More Friction

2. Ex
A 2.0kg free hanging mass is attached to the end of a cord which is attached to a 5.0kg mass resting on a table. If the coefficient of friction between the 5.0kg mass and the table is .20, what is the acceleration of the system?

3. Ex
A 10.0kg box is pulled along a horizontal surface by a forces of 40.0N applied at an angle of 30o. The coefficient of kinetic friction between the box and the surface is Calculate its acceleration.

4. Objects on Inclines

5. When will a block slide down an incline?
If the portion of its weight parallel to the incline is greater than the friction between the surfaces (FGx > Ff)
If FGx is less than friction, the block will not move

6. Ex
A 51.0kg skier is descending down a 30° slope. If the coefficient of friction is .10
a) draw the free body diagram
b) find her acceleration
c) find her speed after 4.0 sec

7. Ex
Suppose that the skier in the previous problem encounters slushy snow and then moves down the slope at a constant speed. What is the new coefficient of friction?